When to scale on your targeting
Scaling your campaign can help when you already have an audience for launch day. It helps you quickly identify who to target and get more signups. It's also great to gain more traction once your project goes viral in the media. Two metrics help determine if it's worth scaling your targeting: your conversion rate and the value of each conversion.
When targeting a large group of people and you're only getting very few conversions, the product could be more appealing to them; there are significant holes in your pitch that need improvement, or both. Make sure you cover all the bases of why someone should signup before executing a scale campaign.